1. Technical Field
The invention relates to the transfer of a fluid which itself is already an injectable product or which forms an injectable product when brought together with a solid or fluid component. The invention further relates to a multi-lumen cannula such as is suitable for transferring a fluid in a particular way.
2. Description of the Related Art
Devices for transferring medicines, mostly using so-called disposable syringes, have been known to patients and medically trained personnel for a long time. Essentially, in the case of a disposable syringe, the cannula is pushed through a puncture membrane of a normal medicine container, then air is pressed through the cannula into the medicine container in order to finally suction medicine from the medicine container through the cannula into the disposable syringe. Normal medicine containers are containers air-tight sealed which have an opening sealed by a puncture membrane.
The same transferring process is also the basis for filling a disposable ampoule which is inserted into an infusion pump or an injection pen. Such infusion pumps are known for example from patent specification EP 0 143 895. Injection pens are known for example from patent specification WO 87/02895. Disposable ampoules differ from disposable syringes in that the cannula can be de-coupled from the rest of the ampoule casing and the stopper from the piston rod. The transferring process is elaborate.
A device for transferring a product fluid from one container into another container is known from CH 676 548 A5, wherein another solid or fluid product is situated in the other container. The other container is sealed at the front end by a puncture membrane and at the rear end by a movable stopper. When transferring the product fluid into the other container, the stopper is pushed further backwards. The product fluid thus comes into contact with an area of the other container which has been previously exposed to the environment. This results in problems of sterility.
More recent injection pens and infusion pumps are designed for the use of so-called pre-filled ampoules, i.e. ampoules which are filled by a medicine manufacturer and not by the patient. Such injection pens or infusion pumps are known from patent specifications WO 93/16740 and WO 98/47552. In order to prevent supply bottle-necks with such pre-filled ampoules, and for the same injection pen or the same infusion pump to be easily used with as many different medicines as possible, the supplier of injection pens and infusion pumps should also provide devices which enable a medicine to be transfused from a normal medicine container into a disposable syringe or disposable ampoule, and then into an ampoule which is preferably filled with a sterile gaseous substance, or otherwise into an ampoule which is identical to the pre-filled ampoule. These ampoules which are preferably filled with a sterile gaseous substance or are otherwise identical to the pre-filled ampoule are called empty ampoules in the following. Empty ampoules consist of an ampoule body which is sealed at its front end by a puncture membrane and at its rear end by a movable stopper. The stopper is arranged at the rear end of the empty ampoule for reasons of sterility. If the medicine is then to be transfused from the disposable ampoule or disposable syringe into the empty ampoule, the sterile gaseous substance has to be displaced, since the stopper arranged at the rear end of the empty ampoule would otherwise be forced out of the empty ampoule.
It is an object of the invention to provide a transferring device for a product fluid which is easily operated by the patient and which enables the product fluid to be transferred into a container which is at least partially filled with gas, without changing the volume of the container.
The object is solved by the subjects of the independent claims.
A transferring device for transferring a product fluid comprises: a first container with a container opening through which the product fluid can be delivered into the first container or out of the first container; a delivering means for delivering the product fluid into the first container or out of the first container; and a cannula which is suitable for piercing a membrane and which comprises a front, first cannula opening. The cannula is or can be connected to the first container via a rear, first cannula opening, such that the product fluid can be delivered through the cannula and the cannula openings into the first container or out of the first container. In accordance with the invention, the cannula comprises a rear, second cannula opening which during transfer forms a fluid connection from a second container to a pressure equalization means or directly to the environment. In this way, a pressure burden or partial vacuum arising from the product fluid being delivered in or out of the second container is decreased without changing the volume of the second container. If the second container is sealed by a piston, no force is exerted on it once the pressure in the second container is equal to the ambient pressure. The piston is prevented from moving.
A fluid connection between the first container and the second container, and a fluid connection between the second container and the pressure equalization means or the environment, is created via the cannula. These fluid connections are established via at least one lumen in the cannula which is connected to the cannula openings. Particularly preferably, the cannula is fixedly connected to the first container. In order to establish a fluid connection, a membrane with which the second container is sealed is pierced through. If both containers are sealed with a membrane, one cannula can be used to establish the fluid connection between the two containers, by the cannula piercing both membranes.
Particularly preferably, the cannula comprises at least two lumens, wherein the fluid connection between the first and the second container is formed by one of the two lumens and the fluid connection between the second container and the pressure equalization means or the environment is formed by the other of the two lumens. One of the at least two through lumens extends from the front, first cannula opening to the rear, first cannula opening and the other of the at least two through lumens extends between a front, second cannula opening and the rear, second cannula opening. The at least two through lumens can be designed in one part, for example by channels or bores. Preferably, a double-lumen tube can be used, whose openings are accordingly connected to the containers. Each through lumen is preferably designed in its own part. Preferably, two conventional hollow injection needles are used, which jointly form the cannula.
The at least two through lumens are preferably arranged side by side. They are particularly preferably arranged parallel. If, for example, two conventional hollow injection needles are used, these can form the cannula spaced parallel. They are preferably fixedly connected to each other, particularly preferably along an outer surface line of the injection needles, respectively.
The puncture membrane of the second container is preferably pierced by the two hollow injection needles. Each injection needle comprises two ends. The front ends of the two injection needles are preferably cut at an angle, to facilitate piercing the membrane. The rear ends of the injection needles are connected to different spaces. The rear end of one injection needle is connected to the first container, for example to the hollow space of a disposable syringe or a disposable ampoule, and the rear end of the other injection needle terminates exposed in the environment. In principle, a connection to the environment can also be established by a differently designed opening on the other injection needle. If, for example, this injection needle is drawn up as far as the ampoule, then the connection to the environment or to another pressure equalization space can for example be formed in this injection needle by a lateral, i.e. radial opening. A fluid connection to the product fluid in the first container exists via one of the two injection needles and not via the other.
In accordance with the invention, the injection needles are collectively designated as the cannula. The two hollow injection needles are preferably arranged axially side by side. The injection needles are preferably connected to each other by a bridge. Particularly preferably, the outer surface areas are connected to each other by welding, soldering or adhesion.
Particularly preferably, one of the at least two through lumens surrounds the other of the at least two through lumens. It can for example be realized by arranging two hollow injection needles with different diameters one inside the other. To form the rear, second cannula opening, the outer injection needle is provided with an opening, for example a slot or a bore. In this way, a space-saving cannula results which can be simply pierced through the membrane by the user.
If two through lumens are provided in the cannula, then the product fluid flows for example out of the first container, via the first through lumen, into the second container, the excess gas, in particular air, simultaneously escaping from the second container through the second through lumen.
Preferably, the cannula only comprises a single through lumen extending from a front cannula opening to a rear, first cannula opening. A rear, second cannula opening is provided between the front cannula opening and the rear, first cannula opening. The rear, second cannula opening is preferably formed by a slot or a hole in the lateral surface area of the cannula. A hollow, one-lumen injection needle can be used as the cannula. Transport of the product fluid between the first container and the second container on the one hand, and pressure equalization between the second container and the pressure equalization means or the environment, take place through the part of the lumen between the front cannula opening and the rear, second cannula opening. The rear, second cannula opening is preferably permeable to gas but not to liquid. A first through lumen is formed by the lumen of the cannula between the front cannula opening and the rear, first cannula opening, and a second through lumen is formed by the lumen between the front cannula opening and the rear, second cannula opening. A section of the lumen of the cannula alternatively or simultaneously forms a part of the first and the second through lumen. A particularly simple cannula is provided which establishes a fluid connection both between the first and the second container and between the second container and a pressure equalization means or the environment.
A cannula is preferably formed by a conventional hollow injection needle whose outer surface area deviates from a circular shape such that, after the membrane is pierced, at least one hollow space remains between the outer surface area of the injection needle and the membrane, such that a fluid connection results between the second container and the environment. The at least one hollow space is preferably formed by at least one groove running along the surface area of the injection needle. The at least one groove is formed such that the membrane does not completely fill it. The fluid connection between the first and the second container is established via the through lumen of the injection needle.
A shortest distance between the front, first cannula opening and the rear, second cannula opening is preferably smaller than a shortest distance between the front, first cannula opening and the rear, first cannula opening. This arrangement of the cannula openings is advantageous if two containers are to be connected to each other and the second container is to be evacuated of air into the environment between the two containers.
The cannulae described above establish the fluid connection between the first and the second container, as well as the fluid connection between the second container and the pressure equalization means or the environment, simultaneously. The cannulae establish the fluid connections by piercing through the membrane of the second container. These fluid connections can be established by a simple linear movement between the first and the second container.
If product fluid is suctioned out of the second container, for example a normal medicine container sealed by a membrane, into the first container, for example a disposable syringe or ampoule, the puncture membrane of the medicine container is pierced by the cannula and the hollow space of the disposable syringe or ampoule is then enlarged, such that product fluid is suctioned through the cannula into the hollow space of the disposable syringe or ampoule. A syringe is preferably provided with a piston which may be moved manually via a piston rod in the syringe. No partial vacuum arises in the normal medicine container, as ambient air simultaneously or near simultaneously enters the normal medicine container through the cannula.
If medicine is to be dispensed from the disposable syringe or ampoule into an empty ampoule, the puncture membrane of the empty ampoule is pierced by the cannula, and the hollow space of the disposable syringe or ampoule is then reduced. Injecting medicine through the cannula does not lead to a pressure burden in the empty ampoule, as the sterile, gaseous substance can escape through the cannula. The cannula preferably includes at least two through lumens, in particular a transport lumen and a ventilation lumen.
In order to make it easier for the patient to pierce through the puncture membrane, the containers involved in the transferring process are preferably clamped in a transferring device which ensures an axial arrangement of the containers and stabilizes the containers with respect to each other.
The transferring device comprises a container holder, which preferably consists of two parts of which each part holds one of the two containers. Both containers comprise a container opening, the two containers being inserted into the transferring device such that the two container openings face each other. The transferring device enables the containers to linearly move towards each other, by way of at least one of the two containers being shiftably supported. A cannula as described above is situated between the two containers, such that when the containers are moved towards each other, a fluid connection is formed between the first and the second container as well as a fluid connection between the second container and the pressure equalization means or the environment.
Both container openings can be sealed by a membrane, wherein the cannula is then pierced through both membranes. The cannula is preferably fixedly connected to one of the two containers and pierces through the membrane sealing the container opening of the other container.
The cannula preferably consists of a transport or connection cannula which connects the two container openings to each other, and a ventilation or compensation cannula which connects the second container to the pressure equalization means or to the environment. The connection cannula and the compensation cannula can be combined in one cannula. They can, however, also be used separately. Particularly preferably, the connection cannula is fixedly connected to the first container and pierces the membrane of the second container sealing the container opening of the second container, when the two containers are moved towards each other. The compensation cannula is situated between the two containers and likewise pierces the membrane of the second container when the containers are shifted towards each other. The compensation cannula is preferably accommodated in a cannula holder which is situated between the two containers. The cannula holder is likewise shiftably held in the device.
The second container is preferably sealed at the front end by a membrane, and at the rear end by a piston. In order to rule out the possibility that, for example, the piston is also not shifted backwards when the ventilation lumen of the cannula is sealed, a protruding part can preferably be provided on the part of the container holder which holds the second container, said protruding part protruding into the second container far enough that said protruding part just abuts the outer end of the piston and thus determines the maximum rear position of the piston in the second container.
The device can be used for a whole succession of transferring and mixing medicines, in various containers.
Particularly preferably, the device is used for transferring a fluid from one container to another container, wherein the fluid itself is a product fluid or forms a product fluid once it is filled together with a solid or fluid component.
Such a transferring device is particularly preferably used as a device for separately storing a first, fluid component and a second, fluid or solid component of the product fluid, and for forming the injectable product fluid by bringing together these components.